ARM: dts: mdm: add sd card support for 9630 mtp

Enable SDHC device node for mdm9630 MTP platform.

CRs-Fixed: 601511
Change-Id: I3795e2e30823b9eb253760f7ee93f6817b20a4e1
Signed-off-by: Krishna Konda <kkonda@codeaurora.org>